ABSTRACT
Background@#Curcumin 2005-8 (Cur5-8), a derivative of curcumin, improves fatty liver disease via AMP-activated protein kinase activation and autophagy regulation. EW-7197 (vactosertib) is a small molecule inhibitor of transforming growth factor β (TGF-β) receptor I and may scavenge reactive oxygen species and ameliorate fibrosis through the SMAD2/3 canonical pathway. This study aimed to determine whether co-administering these two drugs having different mechanisms is beneficial. @*Methods@#Hepatocellular fibrosis was induced in mouse hepatocytes (alpha mouse liver 12 [AML12]) and human hepatic stellate cells (LX-2) using TGF-β (2 ng/mL). The cells were then treated with Cur5-8 (1 μM), EW-7197 (0.5 μM), or both. In animal experiments were also conducted during which, methionine-choline deficient diet, Cur5-8 (100 mg/kg), and EW-7197 (20 mg/kg) were administered orally to 8-week-old C57BL/6J mice for 6 weeks. @*Results@#TGF-β-induced cell morphological changes were improved by EW-7197, and lipid accumulation was restored on the administration of EW-7197 in combination with Cur5-8. In a nonalcoholic steatohepatitis (NASH)-induced mouse model, 6 weeks of EW-7197 and Cur5-8 co-administration alleviated liver fibrosis and improved the nonalcoholic fatty liver disease (NAFLD) activity score. @*Conclusion@#Co-administering Cur5-8 and EW-7197 to NASH-induced mice and fibrotic hepatocytes reduced liver fibrosis and steatohepatitis while maintaining the advantages of both drugs. This is the first study to show the effect of the drug combination against NASH and NAFLD. Similar effects in other animal models will confirm its potential as a new therapeutic agent.
ABSTRACT
Purpose@#Among the characteristics of non-alcoholic fatty liver disease (NAFLD), hepatic steatosis is due to excessive fat accumulation and causes liver damage and lipotoxicity, which are associated with insulin resistance, endoplasmic reticulum (ER) stress, and apoptosis. Umbelliferone (UMB) has various powerful pharmacological properties, such as antioxidant, anti-hyperglycemic, anti-viral, and anti-inflammatory effects. However, the mechanism of action in hepatic steatosis and lipid-induced ER stress is still unclear. Thus, the efficacy of UMB in hepatic steatosis and palmitate (PA)-induced hepatocellular lipotoxicity was evaluated in the present study. @*Materials and Methods@#Male C57BL/6J mice (n=40) were divided into four groups: regular diet (RD), UMB-supplemented RD, high-fat diet (HFD), and UMB-supplemented HFD. All mice were fed orally for 12 weeks. In addition, the effects of UMB on lipotoxicity were investigated in AML12 cells treated with PA (250 μM) for 24 h; Western blot analysis was used to evaluate the changes in ER stress and apoptotic-associated proteins. @*Results@#Administration with UMB in HFD-fed mice reduced lipid accumulation and hepatic triglyceride (TG) as well as serum insulin and glucose levels. In AML12 cells, UMB treatment reduced lipid accumulation as indicated by decreases in the levels of lipogenesis markers, such as SREBP1, FAS, PPAR-γ, and ADRP. Furthermore, UMB reduced both oxidative stress and ER stress-related cellular apoptosis. @*Conclusion@#UMB supplementation ameliorated hepatic steatosis and improved insulin resistance by inhibiting lipid accumulation and regulating ER stress. These findings strongly suggest that UMB may be a potential therapeutic compound against NAFLD.